In an aspect, a method of receiving a data unit, performed by an Access Point (AP), in a Wireless LAN (WLAN) system is provided. The method includes transmitting a signal protection frame, the signal protection frame comprising a group ID field indicating a Multiple Input Multiple Output (MIMO) transmission STA group including a first station (STA) and a second STA; and, a spatial stream field indicating a number of spatial streams allocated to each of member STAs included in the MIMO transmission STA group; receiving a first preamble for a first data unit from the first STA; receiving a second preamble for a second data unit from the second STA; and simultaneously receiving the first data unit from the first STA and the second data unit from the second STA.
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1. A method of receiving a data unit in a Wireless LAN (WLAN) system, comprising: receiving, by an Access Point (AP), control information from each of a plurality of stations (STAs) indicating whether a corresponding station (STA) supports uplink multi-user transmission; receiving, by the AP, access category (AC) information from each of the plurality of STAs indicating an AC of uplink traffic for a corresponding STA; configuring, by the AP, a signal protection frame requesting uplink multi-user transmission, wherein recipients of the signal protection frame are determined by the AP based on the control information, wherein radio resources used for the uplink multi-user transmission are determined by the AP based on the access category (AC) information, and wherein the signal protection frame indicates the recipients of the signal protection frame, spatial streams allocated for the recipients of the signal protection frame, and a time duration used for the uplink multi-user transmission; transmitting, by the AP, a downlink physical layer protocol data unit (PPDU) comprising the signal protection frame to the recipients of the signal protection frame; and simultaneously receiving, by the AP, uplink PPDUs from the recipients of the signal protection frame using the radio resources, wherein each of the uplink PPDUs comprise a preamble field including a Short Training Field (STF) and a Long Training Field (LTF).
An Access Point (AP) in a Wireless LAN (WLAN) system receives data units from multiple stations (STAs) simultaneously using uplink multi-user MIMO. The AP first receives information from each STA indicating if it supports this feature, and also receives information about the priority/type of data (access category, AC) each STA will be sending. Based on this, the AP configures and sends a "signal protection frame" to select STAs. This frame tells the selected STAs that they should transmit, specifies how many data streams each STA can use, and how long the transmission window will last. Finally, the AP simultaneously receives data packets (PPDUs) from these STAs using the agreed-upon radio resources; each data packet contains a preamble with STF and LTF fields to facilitate synchronization and channel estimation.
2. The method of claim 1 , further comprising: waiting, by the AP, during an inter-frame space (SIFS) period after receiving the uplink PPDUs; and transmitting, by the AP, at least one ACK frame indicating an acknowledgement (ACK) of the uplink PPDUs.
After the Access Point (AP) receives the simultaneous data packets (PPDUs) from multiple stations (STAs) as described in the previous transmission method, the AP waits a short inter-frame space (SIFS) period. Following this waiting period, the AP transmits one or more acknowledgement (ACK) frames to confirm the successful reception of the data packets. This acknowledgement indicates that the AP has correctly received the data from the stations in the uplink multi-user transmission.
3. The method of claim 2 , wherein the downlink PPDU and the at least one ACK frame are transmitted during the same transmission opportunity (TXOP).
The downlink physical layer protocol data unit (PPDU) containing the signal protection frame, as well as the acknowledgement frames (ACK) transmitted by the AP, are all sent within the same transmission opportunity (TXOP). This means the entire exchange, including the AP's initial transmission to schedule the uplink multi-user transmission, the simultaneous uplink transmissions from the stations, and the AP's acknowledgements, happens within a single allocated time slot, ensuring efficient use of the wireless medium and minimizing contention with other devices.
4. The method of claim 1 , wherein the control information is 1-bit indicator.
The control information that each station (STA) sends to the Access Point (AP) to indicate whether it supports uplink multi-user transmission is a single bit (1-bit indicator). This simple flag efficiently conveys the STA's capability without requiring extensive overhead, minimizing the initial communication required for the AP to determine which STAs are eligible for simultaneous uplink transmission.
5. A wireless apparatus, comprising: a transceiver that transmits and receives a radio signal; and a processor functionally coupled to the transceiver, wherein the processor: controls the transceiver to receive control information from each of a plurality of stations (STAs) indicating whether a corresponding station (STA) supports uplink multi-user transmission; controls the transceiver to receive access category (AC) information from each of the plurality of STAs indicating an AC of uplink traffic for a corresponding STA; configures a signal protection frame requesting uplink multi-user transmission, wherein recipients of the signal protection frame are determined based on the control information, wherein radio resources used for the uplink multi-user transmission are determined based on the access category (AC) information, and wherein the signal protection frame indicates the recipients of the signal protection frame, spatial streams allocated for the recipients of the signal protection frame, and a time duration used for the uplink multi-user transmission; controls the transceiver to transmit a downlink physical layer protocol data unit (PPDU) comprising the signal protection to the recipients of the signal protection frame; and controls the transceiver to simultaneously receive uplink PPDUs from the recipients of the signal protection frame using the radio resources, wherein each of the uplink PPDUs comprise a preamble field including a Short Training Field (STF) and a Long Training Field (LTF).
A wireless device (Access Point) includes a radio transceiver and a processor. The processor uses the transceiver to: 1) receive support indications from multiple stations, indicating if they support uplink multi-user MIMO; 2) receive access category (AC) information from each STA about the type of data they will send. Based on this info, the processor creates a "signal protection frame" to schedule uplink transmissions, specifying which STAs should transmit, their allowed data streams, and duration. The transceiver then transmits a PPDU containing this frame to selected STAs. Finally, the transceiver receives simultaneous data packets (PPDUs) from these STAs, where each PPDU has a preamble (STF and LTF).
6. The wireless apparatus of claim 5 , wherein the processor further: waits during an inter-frame space (SIFS) period after receiving the uplink PPDUs; and controls the transceiver to transmit at least one ACK frame indicating an acknowledgement (ACK) of the uplink PPDUs.
The wireless device (Access Point) described previously further operates as follows: After simultaneously receiving data packets (PPDUs) from multiple stations (STAs) during uplink multi-user transmission, the processor pauses for a short inter-frame space (SIFS) period. Then, the processor instructs the transceiver to send out acknowledgement (ACK) frames, indicating the successful receipt of the data packets from each of the transmitting stations. This provides feedback to the stations that their data has been received by the access point.
7. The wireless apparatus of claim 6 , wherein the downlink PPDU and the at least one ACK frame are transmitted during the same transmission opportunity (TXOP).
In the wireless apparatus described above, the downlink PPDU containing the signal protection frame (used to schedule the uplink multi-user transmission) and the subsequent acknowledgement frames (ACK) are transmitted within a single Transmission Opportunity (TXOP). This means the entire sequence of events - scheduling, simultaneous uplink transmissions, and acknowledgements - occurs within a pre-defined time window, maximizing spectrum efficiency and reducing the potential for collisions or interference with other devices on the network.
8. The wireless apparatus of claim 5 , wherein the control information is 1-bit indicator.
The control information used by each station to indicate support for uplink multi-user transmission is a simple 1-bit flag. This minimizes overhead in the initial signaling process, allowing the Access Point to quickly determine which stations are capable of participating in simultaneous uplink transmissions. The access point can then effectively manage resources for the uplink transmission.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
November 19, 2015
May 2, 2017
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